Operating Segment Information (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 242,209	$ 232,602	$ 250,682	$ 263,039	$ 227,980	$ 226,696	$ 259,963	$ 265,482	$ 988,532	$ 980,121	$ 964,502
Long-lived assets	517,101				613,386				517,101	613,386	527,979
U.S. [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									789,506	815,850	850,517
Long-lived assets	360,203				404,723				360,203	404,723	317,887
Mexico [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									185,501	150,022	103,273
Long-lived assets	151,752				159,728				151,752	159,728	155,488
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									13,525	12,710	10,712
Long-lived assets	3,787				4,755				3,787	4,755	10,199
U.K. [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									0	1,539	0
Long-lived assets	0				44,138				0	44,138	44,363
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 1,359				$ 42				$ 1,359	$ 42	$ 42